The fifth named storm of the 2015 Atlantic hurricane season, Erika developed from a westward-moving tropical wave while well east of the Lesser Antilles.

Contrary to predictions of a northwesterly recurvature, the cyclone persisted on a westerly course and passed through the Leeward Islands and emerged over the Caribbean Sea on August 27.

The storm's asymmetric structure, coupled with the mountainous terrain of the island and ample moisture aloft, led to rainfall accumulations up to 33 in (850 mm).

With grounds already saturated from antecedent rainfall, tremendous runoff quickly overwhelmed river basins and triggered catastrophic floods.

Hundreds of homes were left uninhabitable and thousands of people were displaced; the entire town of Petite Savanne was evacuated and subsequently abandoned as a result of the storm.

Statistical guidance and the HWRF depicted a hurricane while the ECMWF and GFS showed a weaker system due to increasing wind shear.

[6] This uncertainty ultimately reflected in above-average forecast errors when compared to all tropical cyclones, but roughly average for weak, poorly organized systems.

[8] Early on August 27, Erika managed to intensify slightly, attaining its peak intensity with maximum sustained winds of 50 mph (80 km/h) and a barometric pressure of 1,001 mbar (29.6 inHg).

Based on data from Hurricane Hunters, Erika degenerated into a broad area of low pressure—no longer meeting the definition of a tropical cyclone—shortly after 12:00 UTC, near the southeastern coast of the Dominican Republic.

[18] Officials in Haiti suspended air service, banned highway travel between departments, and ordered small watercraft to remain at port.

[2] Tropical storm-force wind gusts, peaking at 59 mph (95 km/h) in Maricao,[2] caused substantial disruption to the power grid, leaving approximately 250,000 people without electricity.

[44] Farther north in Flagler County, scattered thunderstorms produced isolated instances of heavy rain; 2.2 in (56 mm) fell within one hour in Palm Coast.

[45] In the greater Jacksonville area, lightning struck the Sally B. Mathis Elementary School, resulting in damage to the air conditioning unit and evacuation of students.

[35] Strong winds gusting up to 60 mph (97 km/h) accompanied these storms, downing trees and power lines in Cherokee, Polk, and Troup counties.

Orographic influence exacerbated rainfall rates, and this was further compounded with the formation of a temporary mesoscale low over the island as the primary circulation of Erika continued west.

[2] With grounds already saturated from nearly two weeks of rain prior to Erika, much of the precipitation did not penetrate the surface; in multiple watersheds, runoff exceeded 60 percent of accumulations.

[51] Catastrophic flash flooding and mudslides ensued across the island,[2] resulting in Dominica's worst natural disaster since Hurricane David in 1979.

Flow rates in these localized events vastly exceeded values expected by International Commission on Large Dams modeling.

[31] Dominica Prime Minister Roosevelt Skerrit stated in a national announcement on August 28 that, "The visual damage I saw today, I fear, may have set our development process back by 20 years".

[62][63] The main river running through Roseau, the nation's capital, burst its banks during the overnight of August 26–27, flooding surrounding areas.

[2][68] Residents dug through mud and debris, often with their bare hands, to rescue those trapped and in many cases did so with nearby homes on the verge of collapse.

[69] Immediately following Erika's devastating impact in Dominica on August 27, the Organisation of Eastern Caribbean States convened to determine an assessment plan.

In a report on September 18, they noted that residents in Coulibistrie remained in a state of shock for weeks after Erika, with many struggling to begin the recovery process.

[75] The Ministry of Health highlighted concerns over post-storm diseases, particularly from mosquitoes, due to a major increase in the usage of water storage containers.

[39] The Caribbean Disaster Emergency Management Agency (CDEMA) pledged assistance to Dominica, offering two helicopters with supplies and medics from Trinidad.

[39] The Regional Security System deployed 83 personnel whom conducted search and rescue operations and assisted in the evacuation of hundreds of residents.

[86] The Government of Venezuela airlifted 2,000 tons of food and supplies to Dominica and pledged to provide a helicopter carrier ship on August 29.

[105] The Adventist Development and Relief Agency (ADRA), All Hands Volunteers, Convoy of Hope, ChildFund, and the Organization of American States also provided assistance.

[113] Many were temporarily relocated to the Dominica Grammar School in Roseau; however, members of the public looked upon the evacuees with scorn and insulted them for disrupting their daily lives.

[128] Because of the storm's severe effects on Dominica, the name Erika was retired by the World Meteorological Organization in April 2016, becoming only the second Atlantic basin retiree that never attained hurricane status, along with 2001's Allison.